As described in Patent Document 1, a typical refrigerant heat exchanger includes a plate stack (in the document, plate package) disposed in a lower part of an interior space of a hollow container (in the document, tank) formed into a cylindrical shape. The plate stack includes a plurality of plates (in the document, heat exchange plates) disposed adjacent to one another. The plurality of plates is disposed along the vertical direction, so as to form a first inter-plate space substantially opening into the interior space and configured so that a medium can circulate upward from the lower space of the tank to the upper space, and a second inter-plate space closed against the interior space and configured to circulate a fluid to make the medium capable of vaporizing. An outlet flow path capable of discharging the vaporized medium is formed on an upper part of the plates. An outlet for discharging the vaporized medium is disposed on an upper part of the hollow container.
The plates include an upper part, an intermediate part, and a lower part from top toward bottom, and each part is formed to have a wavy corrugation including protrusions and recesses. Actual heat exchange between the plates is performed via the intermediate part and the lower part. The wavy corrugation of the intermediate part extends in various directions at different positions of the intermediate part. The wavy corrugation extends so that the wavy corrugations of adjacent two plates intersect with each other over the entire intermediate part. With the wavy corrugations extending as described above, the rigidity of the plates is enhanced, and heat is efficiently and reliably transmitted from the fluid to the medium.